What kind of help are you looking for? Do you want someone to completely write the macro for you?

I looked at what might be required (I state might because there are normally a couple ways to get where you want to go).

Looks like you will need to traverse the feature manager tree of the drawing to find all the views. For each view you will need to get the display dimension object for each dimension. Once you have that you can get the primary precision and alternate precision. The trick now is that if the precision is set to the default value the actually precision is not returned you need to look at values set in the document for the dimension type. Of course you need to do this for each dimension in the view then repeat the procedure for each view.

Seems like it will be a fairly complex macro to write. I can probably help you get started...

EDIT: After giving it some more thought, you would only need to get the default precision once (I assume the default is set to two places for mm and three places for alternate inch? If that is the case, when you find the primary is set to default then all you need do is make sure the alternate is set to default.